Expert: John Newman - 1/20/2011

Question
Mr. Newman, I have made many repairs to clocks I own so am capable and have the basic tools.
Some time ago I was fortunate to acquire an original kit for the York Minster Cathedral clock made by Franz Hermle for the Franklin Mint.
The kit was complete and had not been unpackaged since new (more than 30 years ago).
When I built the clock the mainspring did not seem smooth when I wound it the first time.  I came to doubt the condition of the lubricant in the spring.
Since then the clock has run more or less dependably for two winter seasons (it sits idle during the summer).  When started this winter it has refused to run no matter what I do to it.
I believe that the lubricant in the mainspring is old and sticky and that the spring needs cleaning and lubrication.
My problem is that I have the spring barrel out of the clock and the back plate off the barrel so the spring is visible.  I have managed to move the spring enough to unhook it from the tang in the barrel but cannot manage to budge the spring out of the barrel.
I am aware of the safety precautions to use when working with mainsprings and will follow all the precautions to avoid injury to myself or the spring.  I do not wish to damage the barrel or it's cover.  Nor do I wish to 'cone' the spring.
Can you describe for me (or point me toward the place where it is documented) the step-by-step procedure for removing the spring.
Are special tools required?

Thanks for any help you can offer...Joe Whitaker...

Answer
Joe, because of the dangers of working with mainsprings, I do not feel like I can advise someone as to the procedure without actual hands-on supervision.  In the classes I have taught I tell the students that there is a similarity in handling mainsprings and rattlesnakes;  if you do it wrong they will strike and bite you.  I have a pair of gloves with a cut in one where a spring got away, fortunately it cut the glove rather than my hand.  Anyway, I will give you a general idea.  In doing this by hand (as I did before I bought a mainspring winder) you want to put an old blanket in your lap folded a few times.  Using heavy leather gloves, you grasp the barrel with one hand and carefully start unwinding the inner coils of the spring.  The spring should be held off the edge of the barrel to keep it from "shaving off" slivers.  Also you need to inhibit the rapid unwinding of the spring.  It's like starting to move a stick shift car up a hill.  You have to have one foot on the clutch and the other on both the gas pedal and accelerator all at the same time working them to keep from stalling the engine or causing it to shimmy.  Okay, now when you get near the outer end of the spring, you will have to hold and twist the spring at such an angle that it will unhook from the tab in the barrel without crimping the spring.  The mainspring should be cleaned and inspected for pitting and for cracks, particularly near the ends.  Reinstalling it is in reverse of removing it.  

I do have one point, and that is usually the way I check out a clock that isn't running.  You are correct that the lubricants in the mainsprings need replacing, but I would check the complete movement.  Usually the old and gummy oils in the pivots stop a clock before the mainsprings cause problems.  On a clock this old, I would go through the whole cleaning and lubricating procedure.  It is probably just the lubricants rather than any worn parts. Another thought that just came to mind and that is that if a clock has been stored this long, the mainspring lubricant could have done what we call "turned to varnish".  This is when the combination of old grease, heat (like from being stored in an attic) and pressure have completely hardened and caused the coils of the spring to bind together.  Just a thought.  Good luck and let me know how it goes.

John Newman
THE VILLAGE CLOCKSMITH
Old Prattvillage
Prattville, Alabama

Joe, thank you for the nice comments and rating.  In your comment on the lubricants not being bad since the clock has not been run in 30 years, it is my experience (and other clockmakers) that lubricants degrade with age, even though the clock was not running.  Again, I would clean and relubricate the complete clock.  We acquire NOS (New Old Stock) movements that are years old and never been out of the box, and would never think of using one until the lubricants had been replaced.

John Newman

Joe, I read your last statement a little too rapidly and did not see the part where you had re-oiled and greased it.  So please accept my apologies.  John